类的练习书店类具有计算书籍总价，查找书的功能

Question

一个关于类的问题，哪位能帮帮忙
有一个书店类，一个书类，要求书店类具有计算书籍总价，查找书籍的功能

class Bookstore:
    sum_price = 0
    book_index = 0

    def __init__(self):
        self.books = []
        self.books_price=[]

    def add_book(self, title, author, price):
        self.books.append(Book(title, author, price))

    def total_price(self):
        return self.sum_price


    def find_book(self, book_name):

        for obj in self.books:
            if obj.title == book_name:
                return obj.__str__()
            else:
                return "The book could not be found in the book store."

class Book(Bookstore):
    def __init__(self,title,author,price):
        super().__init__()
        self.title=title
        self.author=author
        self.price=price
        Bookstore.book_index += 1
        Bookstore.sum_price += self.price

    def write(self):
        print(self.title, self.author, self.price)
    def __str__(self):
        return f'title:{self.title}\n' \
               f'author:{self.author}\n' \
               f'price:{self.price}'
bs=Bookstore()
b1=Book("高数","清华",20)
b2=Book("现代","清华",23)
total_price=bs.total_price()
print(total_price)
print(Bookstore.find_book("高数"))

报错 TypeError: find_book() missing 1 required positional argument: 'book_name' 怎么解决

Answer 1

在调用 Bookstore.find_book() 方法时需要传入一个参数 book_name，但是在代码中没有传入该参数，导致报错。可以修改代码，在调用 Bookstore.find_book() 方法时传入需要查找的书名，例如：

total_price=bs.total_price()
print(total_price)
print(bs.find_book("高数"))
这样就能正确调用 Bookstore.find_book() 方法，查找书籍信息并输出了。另外需要注意的是，在 Bookstore.find_book() 方法中，查找到书籍后应该直接返回对应书籍的信息，而不是在第一个未匹配到书名的书籍上返回 "The book could not be found in the book store."。修改后的 Bookstore.find_book() 方法如下：
def find_book(self, book_name):
    for obj in self.books:
        if obj.title == book_name:
            return obj.__str__()
    return "The book could not be found in the book store."

```python

这样修改后，当没有找到对应书名的书籍时才会返回 "The book could not be found in the book store."。

```